Jewel-Colored Flies Spell Death for Baby Spiders

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Baby spiders beware: Researchers have just described four new
types of spider flies, whose larvae infect the bloodstream of
juvenile spiders.

A paper published March 1 in the journal Zookeys catalogs the
huge variety of spider flies in Australasia, including four
genera whose larvae specialize in parasitizing spiders like
tarantulas, trap door spiders and funnel web spiders. Genera
are a scientific classing of organisms that includes species;
these ones belong to the subfamily Panopinae and live in
the area of the world that includes Asia, Australia, New Guinea
and Indonesia.

"It’s a very charismatic group and very interesting, but it's
very rarely collected and hadn't been worked on in many years,"
study researcher Shaun Winterton, of the California Department of
Food & Agriculture, told LiveScience. "We wanted to make the
knowledge we had available to the scientific community."

Winterton also discovered four new species of Panops
from Australia. They are P. aurum and P.
danielsi, which have large eyes and golden manes, and P.
jade and P. schlingeri, which have a greenish-blue
sheen and whitish hairs around their heads. The flies' metallic
coloration gives them their jewel-like appearance. [ Images
of Jewel-Colored Spider Flies ]

Spiders beware

All species in Panops have larvae that become parasites
inside Australian spiders. The adult sprays its eggs in places
traversed by juvenile spiders. When the larvae emerge, they wait
for a spider to pass, then climb aboard one of its legs. When the
spider starts moving, the spider-fly larvae sneak into the
spider's bloodstream.

"They specialize in big
spiders like tarantulas. Those spiders can live for years at
a time," Winterton said. "When they have the maggot inside the
spider, it actually extends the spider's life; they can live like
that for up to 10 years."

Eventually, however, the spider-fly maggot will
eat the spider from the inside out, leaving behind only the
exoskeleton, then will wrap itself in the spider's web and
develop into an adult in about a week to 10 days.

Flying jewels

These adult spider flies are not all bad news; they're important
pollinators of flowers.

In some species of Panops, the mouthparts are greatly
elongated to allow the owner to
feed at flowers with nectar at the base of long corolla
tubes. Others have very oddly shaped bodies that resemble the
creature in the 1979 movie "Alien."

Others have bright
iridescent colorations, perhaps to mimic bees. Still others
are covered in hairs that all point forward, and when you look at
their faces, they almost look like snowmen or big fuzzy
bumblebees. "It changes color to a beautiful white, fuzzy beast,"
Winterton said.

As for his favorite spider fly, that's an easy question:
"Panops jade," Winterton told LiveScience. "I named it
after my daughter, Jade."

You can follow LiveScience staff writer Jennifer Welsh on
Twitter @microbelover.
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